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As per the title, I'm getting this error when I try to call getDrawablesList() and setupUI() in my ImageSectionFragment().

getDrawablesList() and setupUI() were tested in a separate project called in onCreate() and they worked perfectly fine.

I suspect it has something to do with how I call them here in the FragmentActivity.

Any help would be greatly appreciated.

public class MainActivity extends FragmentActivity {
    SectionsPagerAdapter mSectionsPagerAdapter;
    ViewPager mViewPager;
    public String SERVERIP;
    private TCPClient mTcpClient;
    private ArrayList<String> arrayList;
    private ImageView selectedImageView;
    private ImageView leftArrowImageView;
    private ImageView rightArrowImageView;
    private Gallery gallery;
    private int selectedImagePosition = 0;
    private List<Drawable> drawables;
    private GalleryImageAdapter galImageAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_page);
        arrayList = new ArrayList<String>();
        Bundle extras = getIntent().getExtras();
        SERVERIP = extras.getString("key");
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the app.
        mSectionsPagerAdapter = new SectionsPagerAdapter(
                getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        if (SERVERIP == "null") {
            Log.d("MainActivity.java", "Continue without connection selected");
        }

        else {
            new connectTask().execute("");
        }
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a DummySectionFragment (defined as a static inner class
            // below) with the page number as its lone argument.
            /*
             * Fragment fragment = new DummySectionFragment(); Bundle args = new
             * Bundle(); args.putInt(DummySectionFragment.ARG_SECTION_NUMBER,
             * position + 1); fragment.setArguments(args); return fragment;
             */
            Fragment fragment = new Fragment();
            if (position == 0) {
                fragment = new DummySectionFragment();
            }

            else if (position == 1) {
                fragment = new ImageSectionFragment();
            }

            return fragment;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            Locale l = Locale.getDefault();
            switch (position) {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);
            case 2:
                return getString(R.string.title_section3).toUpperCase(l);
            }
            return null;
        }
    }

    /**
     * A dummy fragment representing a section of the app, but that simply
     * displays dummy text.
     */
    public static class DummySectionFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        public DummySectionFragment() {

        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_textpage,
                    container, false);
            return rootView;
        }
    }

    public static class ImageSectionFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        MainActivity ma = new MainActivity();
        public ImageSectionFragment() {

        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_imagepage,container, false);
            ma.getDrawablesList();
            ma.setupUI();
            return rootView;
        }


    }

    private void setupUI() {

        selectedImageView = (ImageView) findViewById(R.id.selected_imageview);
        leftArrowImageView = (ImageView) findViewById(R.id.left_arrow_imageview);
        rightArrowImageView = (ImageView) findViewById(R.id.right_arrow_imageview);
        gallery = (Gallery) findViewById(R.id.gallery);

        leftArrowImageView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                if (selectedImagePosition > 0) {
                    --selectedImagePosition;

                }

                gallery.setSelection(selectedImagePosition, false);
            }
        });

        rightArrowImageView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                if (selectedImagePosition < drawables.size() - 1) {
                    ++selectedImagePosition;

                }

                gallery.setSelection(selectedImagePosition, false);

            }
        });

        gallery.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {

                selectedImagePosition = pos;

                if (selectedImagePosition > 0 && selectedImagePosition < drawables.size() - 1) {

                    leftArrowImageView.setImageDrawable(getResources().getDrawable(R.drawable.arrow_left_enabled));
                    rightArrowImageView.setImageDrawable(getResources().getDrawable(R.drawable.arrow_right_enabled));

                } else if (selectedImagePosition == 0) {

                    leftArrowImageView.setImageDrawable(getResources().getDrawable(R.drawable.arrow_left_disabled));

                } else if (selectedImagePosition == drawables.size() - 1) {

                    rightArrowImageView.setImageDrawable(getResources().getDrawable(R.drawable.arrow_right_disabled));
                }

                changeBorderForSelectedImage(selectedImagePosition);
                setSelectedImage(selectedImagePosition);
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {

            }

        });

        galImageAdapter = new GalleryImageAdapter(this, drawables);

        gallery.setAdapter(galImageAdapter);

        if (drawables.size() > 0) {

            gallery.setSelection(selectedImagePosition, false);

        }

        if (drawables.size() == 1) {

            rightArrowImageView.setImageDrawable(getResources().getDrawable(R.drawable.arrow_right_disabled));
        }

    }

    private void changeBorderForSelectedImage(int selectedItemPos) {

        int count = gallery.getChildCount();

        for (int i = 0; i < count; i++) {

            ImageView imageView = (ImageView) gallery.getChildAt(i);
            imageView.setBackgroundDrawable(getResources().getDrawable(R.drawable.image_border));
            imageView.setPadding(3, 3, 3, 3);

        }

        ImageView imageView = (ImageView) gallery.getSelectedView();
        imageView.setBackgroundDrawable(getResources().getDrawable(R.drawable.selected_image_border));
        imageView.setPadding(3, 3, 3, 3);
    }

    private void getDrawablesList() {

        drawables = new ArrayList<Drawable>();
        drawables.add(getResources().getDrawable(R.drawable.natureimage1));
        drawables.add(getResources().getDrawable(R.drawable.natureimage2));
        drawables.add(getResources().getDrawable(R.drawable.natureimage3));
        drawables.add(getResources().getDrawable(R.drawable.natureimage4));
        drawables.add(getResources().getDrawable(R.drawable.natureimage5));
        drawables.add(getResources().getDrawable(R.drawable.natureimage6));
        drawables.add(getResources().getDrawable(R.drawable.natureimage7));
        drawables.add(getResources().getDrawable(R.drawable.natureimage8));
        drawables.add(getResources().getDrawable(R.drawable.natureimage9));
        drawables.add(getResources().getDrawable(R.drawable.natureimage10));
        drawables.add(getResources().getDrawable(R.drawable.natureimage11));
        drawables.add(getResources().getDrawable(R.drawable.natureimage12));
        drawables.add(getResources().getDrawable(R.drawable.natureimage13));
        drawables.add(getResources().getDrawable(R.drawable.natureimage14));
        drawables.add(getResources().getDrawable(R.drawable.natureimage15));

    }

    private void setSelectedImage(int selectedImagePosition) {

        BitmapDrawable bd = (BitmapDrawable) drawables.get(selectedImagePosition);
        Bitmap b = Bitmap.createScaledBitmap(bd.getBitmap(), (int) (bd.getIntrinsicHeight() * 0.9), (int) (bd.getIntrinsicWidth() * 0.7), false);
        selectedImageView.setImageBitmap(b);
        selectedImageView.setScaleType(ScaleType.FIT_XY);

    }

    public class connectTask extends AsyncTask<String, String, TCPClient> {

        @Override
        protected TCPClient doInBackground(String... message) {

            // we create a TCPClient object and
            mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() {
                @Override
                // here the messageReceived method is implemented
                public void messageReceived(String message) {
                    // this method calls the onProgressUpdate
                    publishProgress(message);
                }
            });
            mTcpClient.run(SERVERIP);

            return null;
        }

        @Override
        protected void onProgressUpdate(String... values) {
            super.onProgressUpdate(values);

            // in the arrayList we add the messaged received from server
            arrayList.add(values[0]);
            // notify the adapter that the data set has changed. This means that
            // new message received
            // from server was added to the list

        }
    }
}

Here is the logcat

07-16 14:21:48.664: E/AndroidRuntime(26188): FATAL EXCEPTION: main
07-16 14:21:48.664: E/AndroidRuntime(26188): java.lang.NullPointerException
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.content.ContextWrapper.getResources(ContextWrapper.java:81)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.fypj.mdm.MainActivity.getDrawablesList(MainActivity.java:273)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.fypj.mdm.MainActivity.access$0(MainActivity.java:270)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.fypj.mdm.MainActivity$ImageSectionFragment.onCreateView(MainActivity.java:160)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:461)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.view.ViewPager.populate(ViewPager.java:1064)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.view.ViewPager.populate(ViewPager.java:911)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1432)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.View.measure(View.java:15481)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5107)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.View.measure(View.java:15481)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.widget.LinearLayout.measureVertical(LinearLayout.java:833)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.View.measure(View.java:15481)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5107)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2361)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.View.measure(View.java:15481)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1999)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1238)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1413)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1131)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4611)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.Choreographer.doCallbacks(Choreographer.java:555)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.Choreographer.doFrame(Choreographer.java:525)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.os.Handler.handleCallback(Handler.java:615)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.os.Handler.dispatchMessage(Handler.java:92)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.os.Looper.loop(Looper.java:137)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at android.app.ActivityThread.main(ActivityThread.java:4898)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at java.lang.reflect.Method.invokeNative(Native Method)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at java.lang.reflect.Method.invoke(Method.java:511)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
07-16 14:21:48.664: E/AndroidRuntime(26188):    at dalvik.system.NativeStart.main(Native Method)
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3  
Use a debugger, find out what is actually NULL and fix that. –  Bart Friederichs Jul 16 at 6:17
 
MainActivity ma = new MainActivity() why this in Fragment? –  Raghunandan Jul 16 at 6:22
 
@Raghunandan Hi, because ImageSectionFragment is a static class, it is necessary in order to call setupUI() and getDrawableLists() since they are both non static methods in MainActivity. If I'm not wrong? Haha, but it fixed the static reference to non static method error. –  SpencerChantler123 Jul 16 at 6:25
 
@SpencerChantler123 also selectedImageView = (ImageView) findViewById(R.id.selected_imageview) shoudl be selectedImageView = (ImageView)rootview. findViewById(R.id.selected_imageview) –  Raghunandan Jul 16 at 6:27
 
@Raghunandan, rootView is not a local variable to setupUI() because it was only declared in my fragment and setupUI() is a separate method so I would get an error if i did that. Are you suggesting me to put everything inside the fragment instead? –  SpencerChantler123 Jul 16 at 6:31
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1 Answer

up vote 0 down vote

You cannot instantiate an Activity like this

 MainActivity ma = new MainActivity();

What you need to do is override onAttach(Activity) in your fragment and Assign the activity to ma

    Activity ma;

    public void onAttach (Activity activity){
         ma = activity;
    }

Or use getActivity() method to get Activity wherever you need it

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